Geomorphological and spectrophotometric analysis of Seth's circular niches on comet 67P/Churyumov-Gerasimenko using OSIRIS images

DOI: 
10.1093/mnras/stx1590
Publication date: 
01/07/2017
Main author: 
Lucchetti, A.
IAA authors: 
Gutierrez, P. J.;Lara, L. M.;Lin, L. Z.;Lopez Moreno, J. J.
Authors: 
Lucchetti, A.;Pajola, M.;Fornasier, S.;Mottola, S.;Penasa, L.;Jorda, L.;Cremonese, G.;Feller, C.;Hasselmann, P. H.;Massironi, M.;Ferrari, S.;Naletto, G.;Oklay, N.;Sierks, H.;Barbieri, C.;Lamy, P. L.;Rodrigo, R.;Koschny, D.;Rickman, H.;Keller, H. U.;Agarwal, J.;A'Hearn, M. F.;Barucci, M. A.;Bertaux, J. L.;Bertini, I.;Boudreault, S.;Da Deppo, V.;Davidsson, B.;Debei, S.;De Cecco, M.;Deller, J.;Fulle, M.;Groussin, O.;Gutierrez, P. J.;Güttler, C.;Hoffman, M.;Hviid, S. F.;Ip, W. H.;Knollenberg, J.;Kramm, J. R.;Kührt, E.;Küppers, M.;Lara, L. M.;Lazzarin, M.;La Forgia, F.;Lin, L. Z.;Lopez Moreno, J. J.;Marzari, F.;Preusker, F.;Scholten, F.;Shi, X.;Thomas, N.;Tubiana, C.;Vincent, J. B.
Journal: 
Monthly Notices of the Royal Astronomical Society
Refereed: 
Yes
Publication type: 
Article
Volume: 
469
Pages: 
S238-S251
Abstract: 

We provide a detailed geomorphological and spectrophotometric analysis of the circular niches located on the Seth region of 67P using OSIRIS images. The features can be related to landslide events that occurred on 67P and shaped its surface, as the recent Aswan cliff collapse detected in the same region. We therefore provide an analysis of the area pre- and post-perihelion suggesting that no specific changes have been observed. To assess this, after performing a geomorphological map of the area that allows us to identify different terrain units, we computed the boulders cumulative size frequency distribution (SFD) of the niches, before and after the perihelion passage. The niches SFDs are characterized by a similar trend with two different power-law indices within the same deposit: lower power-law value (between -2.3 and -2.7) for boulders smaller than 5 m and steeper power-law value (between -4.7 and -5.0) for boulders larger than 5 m. These trends suggest that smaller boulders have evolved and progressively have been depleted (lower power-law index), while bigger boulders are more representative of the event that generated the deposit and are less degraded. Then, we perform the spectrophotometric analysis of this region comparing pre- and post-perihelion results. We found colour changes within the area, in particular brighter patches related to the presence of exposed water ice mixed to the refractory materials have been detected in the post-perihelion images.

Database: 
ADS
SCOPUS
URL: 
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85037044442&doi=10.1093%2fmnras%2fstx1590&partnerID=40&md5=7dce8f56983c92e7fa2c19e2b4a47db4
ADS Bibcode: 
2017MNRAS.469S.238L
Keywords: 
methods: data analysis;comets: general;comets: individual: 67P/Churyumov-Gerasimenko